<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>函数的返回值</title>
	</head>
	<body>
	</body>
	<script>
		//如果没有return 函数就没有返回值 值为 undefined
		//但是如果只写了return 值也是undefined；
		function sum(a,b,c){
			var d =a+b+c;
			return "hello";
		}
		var result=sum(1,3,5)
		//var result=sum(1,8,3)
		console.log(result)
	</script>
</html>
